JP3999537B2 - Electrode guide device for small hole electric discharge machine - Google Patents

Description

[0001]
[Technology to which the Invention belongs]
The present invention relates to a fine hole electric discharge machine equipped with an electrode guide having a guide hole through which the tip of the fine hole machining electrode of the fine hole electric discharge machine can be inserted and rotated, and particularly when the electrode guide is replaced. The present invention relates to a fine hole electric discharge machine equipped with an electrode guide device that automatically and reliably performs a fine hole machining electrode positioning operation by machine-specific contact sensing.
[0002]
[Prior art]
The fine hole electric discharge machine 1 is an apparatus that uses a long thin conductive pipe as an electrode and cuts a fine hole in a workpiece by electric discharge machining. The configuration is configured as shown in FIGS. 9 and 10, for example.
[0003]
In the figure, 2 is a bed, 3 is a Y-axis drive device, 4 is a saddle provided on the bed 2 and is moved in the Y-axis direction by the Y-axis drive device 3, 5 is an X-axis drive device, and 6 is a saddle 4. A table 7 provided on the table and moved in the X-axis direction by the X-axis driving device 5 is a processing tank provided on the table 6.
[0004]
8 is a workpiece, 9 is a reference sphere for touch detection, which will be described later, and these are provided at a fixed reference position on the table 6.
[0005]
Reference numeral 10 denotes a column provided on the rear side of the bed 2, and 11 denotes a W-axis drive device. In the drawing, a ball-screw 11A and a rotary electric motor 11B are used, and a W-axis slider held on the column 10 via a linear guide 11C. 12 and the slider body 12A are moved up and down. 11D is a rotary encoder that detects the positions of the sliders 12 and 12A and controls the motor 11B in accordance with the NC command, and 13 is a Z-axis drive device. In the figure, a linear motor 13 comprising a combination of a magnet plate 13A and an electromagnet 13B is provided. I use it. Reference numeral 14 denotes a Z-axis slider held by the slider main body 12A via a linear guide 14A, which constitutes a machining head that moves in the Z-axis direction by a Z-axis drive device 13 provided in the slider main body 12A.
[0006]
15 is a spindle rotation driving device, 16 is a machining spindle provided on the machining head 14 and driven to rotate by the spindle rotation driving device 15, and 18 is a thin electrode held by an electrode holder 18 </ b> A that is replaceably mounted on the machining spindle 16. In the hole machining electrode, the machining feed of the Z axis is controlled by the machining head 14.
[0007]
An electrode guide device 20 includes an electrode guide 21, a guide base 22, a connection bracket 23, and an intermediate guide 24 as follows.
[0008]
An electrode guide 21 is inserted through the tip of the fine hole machining electrode 18 to guide it to the electric discharge machining portion, and 22 is arranged at a predetermined machining position holding the electrode guide 21 and approaching the surface of the workpiece 8. Guide mounting base.
[0009]
23 is a connecting bracket for connecting and supporting the guide mounting base 22 to the slider body 12A, and 24 is an electrode 18 provided between the electrode holder 18A and the mounting base 22 of the electrode guide 21 so as to be movable as required. One or more intermediate guides that prevent the intermediate portion from swinging.
[0010]
In such a fine hole electric discharge machine 1, a thin rod electrode or pipe electrode having a circular cross section is used as the fine hole machining electrode 18 (hereinafter referred to as electrode 18). The electrode 18 having an outer diameter corresponding to the machining hole diameter is prepared by being attached to the electrode holder 18A. The electrode 18 is gripped by the tip of the machining spindle 16 and is loosely fitted into the guide hole of the electrode guide 21 in a rotating state during electric discharge machining. It is inserted.
[0011]
The electrode guide 21 has a die guide made of ruby or the like having an inner diameter corresponding to the outer diameter of the electrode provided in the guide hole, and is connected to a slider main body 12A movable in the vertical direction (W-axis direction). It is detachably held by the mounting base 22 held by 23. Then, the height of the mounting base 22 is positioned by the vertical movement of the slider body 12A so that the lower end surface of the electrode guide 21 is in close contact with the upper surface of the processed portion of the workpiece 8, and the electrode 18 The tip is accurately positioned at the machining position close to the surface of the workpiece 8.
[0012]
In this state, when a machining voltage pulse is applied between the electrode 18 and the workpiece 8 and is discharged under the presence of a machining liquid, machining is started and a machining hole is formed. When a servo feed is given to the electrode 18 by the Z-axis drive device 13 so as to enter the machining hole, the fine hole machining is performed. Further, the generating process can be performed by giving a servo feed so that the electrode 18 and the electrode guide 21 are moved relative to the workpiece 8 in the horizontal direction along a predetermined processing locus.
[0013]
In order to perform the fine hole electric discharge machining in which the electrode 18 is accurately positioned at the desired machining position of the workpiece 8, the coordinate position of the workpiece 8 and the center coordinate position of the electrode tip are accurately set before the machining is started. Must be stored in the controller of the electric discharge machine. For this reason, normally, the coordinate position of the electrode 18 or the electrode-side reference portion with respect to the reference sphere 9 is detected and stored by the contact sensing means. Further, the installation of the reference sphere 9 is simply omitted, and the predetermined position of the workpiece 8 and the center or side surface position of the electrode 18 are detected and stored by contact sensing between them. In the contact sensing, a slight direct current or alternating voltage is applied between a contact sensing detection member or electrode 18 attached to the machining spindle 16 side and a positioning member such as the workpiece 8 or a reference sphere 9. Then, the coordinate positions of the machining spindle 16, the electrode 18, the reference sphere 9 and the work piece 8 such as the center and end face are detected from the coordinate position of the contact portion when the two are brought into contact and conducted. It is a function to calculate.
[0014]
Positioning using this touch sensing is a well-known technique, but is briefly shown below by an example in which a reference sphere 9 is used. First, contact sensing is performed at a preparation stage before the start of electric discharge machining. At this time, as shown in FIG. 7, a conductive cylindrical member (hereinafter referred to as a stylus 40) is attached to the machining spindle 16 or the electrode guide 21 as a contact-sensitive electrode-side detection member. Specifically, a long stylus 40 that reaches under the electrode guide 21 is attached to the machining spindle 16, or a short stylus 40 is attached to the electrode guide 21 or the attachment base 22. The stylus 40 or the guide 21 and the reference sphere 9 move relative to each other in the horizontal direction, so that the stylus 40 senses contact with the reference sphere 9 from four directions of two orthogonal axes in the horizontal plane, and contacts with the stylus 40 at that time. Each coordinate position is detected. The center coordinate position (average coordinate position) of these coordinate positions is calculated by a control device (not shown) and stored as the center coordinate position of the reference sphere 9 (electrode center position determination).
[0015]
The position of the workpiece 8 is obtained as follows by contact detection between the stylus 40 and the workpiece 8 and stored in the control device. The stylus 40 senses contact with one reference side surface of the workpiece 8 from one horizontal direction (not shown), and the coordinate position contacting the end surface of the workpiece 8 is detected. The radius of the stylus 40 is detected from this coordinate position. The coordinate position whose distance has been corrected is set as one reference end face position of the workpiece 8 (end face position finding). Similarly to the contact sensing for the reference sphere 9, the stylus 40 senses contact from both sides of the workpiece 8 from both the forward and reverse horizontal directions (not shown), and the center value of the detected two coordinate positions ( From the average value, the center coordinate position of the workpiece 8 is set as the center position (center position determination).
[0016]
In this way, the relative coordinate position of the workpiece 8 with respect to the reference sphere 9 is detected. In many cases, the coordinate positions of the reference sphere 9 and the workpiece 8 are set in the control device as the origins of the different coordinate systems. The operator creates a subsequent machining program based on these coordinate origin positions and a control axis movement program for contact detection performed as necessary, and thereafter, electric discharge machining and contact detection are automatically performed by this program. It is.
[0017]
Next, in the case of fine hole electric discharge machining, the electrode 18 is attached to the machining spindle 16, and the electrode guide 21 corresponding to the electrode diameter is attached to the attachment base 22. As shown in FIGS. 7 and 8, the rotating electrode 18 protruding below the electrode guide 21 is rotated from four directions of two orthogonal axes in the horizontal plane with respect to the reference sphere 9 serving as the coordinate origin. Although the contact is sensed, from a relative viewpoint, the reference sphere 9 is also sensed by touching the electrode 18 from four directions of two orthogonal axes in the horizontal plane. Coordinates can be obtained.
The electrode guide 21 is replaced when the die guide is worn or when an electrode 18 having a different diameter is used. After the electrode guide 21 is replaced, the center position of the electrode positioned by the guide 21 slightly changes. There are many cases. For this reason, it is necessary to obtain and correct the electrode center position coordinate to be guided every time the electrode guide 21 is replaced. The reason why the electrode 18 needs to be rotated is that there is a slight gap between the electrode 18 and the guide hole of the electrode guide 21 and the die guide in addition to the reason for processing performance.
[0018]
After the preparatory work as described above is performed, the electrode 18 is accurately positioned on a desired machining position, and electric discharge machining is started. If the reference sphere 9 is not installed and only the workpiece 8 is touched, the center position of the workpiece 8 or the center axis of the stylus coincides with the reference position of the reference end face. Set to do. The contact sensing operation at this time is performed in the same manner as that for the workpiece 8 described above.
[0019]
[Problems to be solved by the invention]
However, in the above-described conventional technology, when the diameter of the narrow hole processing electrode 18 is about φ0.5 mm or more and thick, the electrode has rigidity, so that its rotational runout and deformation do not occur, and the reference Although the touch detection pressing operation can be performed on the sphere 9 as described above, when the electrode 18 has a smaller diameter, the contact detection by the reference sphere 9 makes accurate coordinate detection positioning for the following reason. Was difficult.
That is, as shown in FIG. 8, when the contact sensing portion of the reference sphere 9 is a sphere, the projection allowance of the electrode 18 from the electrode guide 21 must be at least the radius of the sphere, and the projection allowance of the electrode 18 Becomes larger. In addition, the rigidity of the electrode 18 is small. Therefore, the rotational deflection of the electrode 18 increases, and when the rotating electrode comes into contact with the sphere, the electrode 18 often collides with the side surface of the sphere, and the electrode is easily biased and deformed. As a result, each time the electrode 18 senses contact with the reference sphere 9, an indefinite bias or deformation occurs, and position detection by contact sensing becomes inaccurate.
[0020]
Therefore, conventionally, when the electrode 18 has a small diameter, the center position of the electrode is obtained by detecting contact with the reference end surface of the workpiece 8 so that the protrusion of the electrode 18 is small. However, inaccuracy is unavoidable even in this center positioning. This is because the amount of runout changes due to variations in the electrode protrusion, and the apparent electrode radius changes with respect to the electrode radius for correcting the electrode diameter. In addition, if the electrode tip is damaged in addition to the deflection and deformation of the electrode during the contact sensing, the straightness of the processed hole is adversely affected.
[0021]
In the situation where the center position of the electrode for small hole electric discharge machining is unavoidable by such contact sensing, in recent years, an automatic electrode exchange device has been provided, and plural types of electrodes 18 having the same diameter or different diameters can be exchanged. However, the number of small-hole electric discharge machines that perform continuous machining is increasing. In this type of small hole electric discharge machine, the electrode guide 21 is also automatically replaced. After the replacement of the electrode guide 21, the center position of the electrode 18 must be determined. For this reason, the necessity for accurate positioning of the electrode 18 by contact sensing is increasing more and more.
[0022]
In view of the above, the present invention provides a fine hole electric discharge machine that can more easily and accurately detect contact, and that can be easily automated. That is, it is an object of the present invention to provide a fine hole electric discharge machine that does not cause the above-described inconvenience in contact sensing in the case of a small diameter electrode and can cope with automatic replacement of an electrode guide.
[0023]
[Means for Solving the Problems]
The objects of the present invention are as follows: (1) A plurality of electrode guides that guide the electrical discharge machining part through the tips of rotating fine hole machining electrodes having the same or different diameters, and a desired plurality of electrode guides are accommodated. In an electrode guide device of a fine hole electric discharge machine having attachment means for attaching and exchanging between an electrode magazine to be performed and an electrode guide attachment base of the electric discharge machining part,
Each of the electrode guides is a cylindrical body as a whole, has a guide hole through which the electrode is inserted and a positioning guide provided in the guide hole, and is concentric with the positioning guide in the guide hole. A cylindrical outer peripheral surface formed of a conductor material which is formed and is in contact with and away from a reference member for horizontal positioning contact sensing, and the electrode guide is attached to the mounting base of the electric discharge machining portion by the mounting means. The lower end side of the guide is mounted in a state protruding a predetermined length from the lower end surface of the mounting base, and the outer peripheral surface of the guide is automatically connected to one terminal of the contact sensing means at the mounting base portion. This is achieved by providing an electrode guide device for a fine hole electric discharge machine.
[0024]
Also, the object of the present invention is as follows: (2) a plurality of electrode guides that pass through the rotating fine hole machining electrodes having the same or different diameters and guide them to the electric discharge machining unit; An electrode guide mounting base that is held at a predetermined interval on a straight line or an arc line in a direction intersecting with the axial direction, and driving the mounting base in the direction intersecting with the axial direction of the electrode. In an electrode guide device of a fine hole electric discharge machine having a driving means for positioning one on the electric discharge machining part,
Each of the electrode guides is a cylindrical body as a whole, has a guide hole through which the electrode is inserted and a positioning guide provided in the guide hole, and is concentric with the positioning guide in the guide hole. And a cylindrical outer peripheral surface made of a conductor material contacting and separating from the reference member for contact detection in positioning in the intersecting direction, and the electrode guide is below the guide mounting base of the holding means. The outer peripheral surface of the corresponding electrode guide mounted on the predetermined electric discharge machining portion by the driving means is electrically connected automatically to one terminal of the contact sensing means. This is achieved by providing an electrode guide device for a fine hole electric discharge machine provided with the above means.
[0025]
The above-mentioned object of the present invention is as follows: (3) The electrode guide further has a concentric reference centered on the guide hole that contacts and separates the reference member for positioning contact sensing in the electrode axial direction on the lower surface of the lower end. This is achieved by using the electrode guide device of the fine hole electric discharge machine according to (1) or (2), wherein the lower end surface is formed.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal sectional view of an embodiment of an electrode guide portion of an electrode guide apparatus according to the present invention. In the figure, the electrode guide 25 is composed of an outer cylinder 25A made of a conductive material such as stainless steel, and an inner cylinder sleeve 25B made of ceramics. The inner cylinder 25B has one guide hole 25C for inserting and guiding the electrode 18 and a plurality of die guides 25D made of ruby or the like for insertion and positioning at a predetermined interval as shown. Since the cylindrical outer peripheral surface 25E of the outer cylinder 25A serves as a reference surface for contact with and separation from the reference member at the time of positioning by horizontal contact sensing described later, the guide hole 25C of the inner cylinder sleeve 25B It is finished precisely concentrically with the supporting die guide 25D.
[0027]
In addition, the electrode guide 25 has a guide hole 25C, which is positioned by contact sensing in the axial direction of the electrode 18 to be inserted and guided, that is, in the depth direction of the machining fine hole, on the lower surface of the lower end. A concentric circular reference lower end face 25F as the center is formed with accurate dimension control. Reference numeral 25G denotes an annular groove for attaching a C-shaped retaining ring. As will be described later, the electrode guide 25 can also be used as an attachment position reference when the electrode guide 25 is inserted and attached to the guide attachment base of the electrode guide device.
[0028]
FIG. 2 is a longitudinal sectional view of another embodiment of the electrode guide 25, and the whole body portion 25AB composed of the outer cylinder 25A and the inner cylinder 25B of the above-described embodiment is made of a conductor material such as stainless steel. The structure of the other part is substantially the same as that of FIG.
In the present invention, as will be described later, the outer peripheral surface 25A of the cylindrical electrode guide 25 and at least the outer peripheral surface of the distal end portion of the guide 25 are made of a conductive material for contact sensing or have some conductivity. While it is necessary to make it electrically conductive by a property imparting process or the like, when it is attached to the attachment base 22, the processing machine is connected via the attachment base 22, the connection bracket 23, or the slide body 12A. It is necessary to be insulated and held so as not to be connected to the main body or the ground. In some cases, it is often preferable that the conductive portion is kept insulated from the electrode 18.
[0029]
FIG. 3 is an enlarged cross-sectional view of a main part of one embodiment of the present invention in which one electrode guide 25 as described above is provided in the guide mounting base 22 portion of the electrode guide device of the fine hole electric discharge machine. Although not shown in the drawing, a plurality of electrode guides 25 for inserting and positioning electrodes 18 having the same or different diameters, or a desired plurality of electrode guide holders to which the respective electrode guides are attached are stored. Electrode guide or electrode guide holder magazine, electrode guide exchange means for attaching and replacing the electrode guide or electrode guide holder between the electrode guide magazine and the guide mounting base 2 of the electrode guide device, and their automatic Although the operation control device and the like are well-known, they are not shown. For example, in the illustrated case, the electrode guide 25 corresponds to the wear of the die guide 25D, the use of the different-diameter electrode 18, and the like. In the insertion hole 22A, the guide replacement means is replaced and attached by automatic insertion / removal from above. To. Reference numeral 19 denotes a protective lid that also serves as an electrode guide.
[0030]
The electrode guide 25 is electrically connected to the connecting bracket 23 for attaching the guide mounting base 22 to the W-axis slider main body 12A, and further to the mounting base 22 using appropriate ceramics or engineering plastics, and further using the sleeve or bushing. Installed in an insulated state. The electrode guide 25 has a cylindrical outer peripheral surface 25E formed precisely concentrically with the guide hole 25C and the die guide 25D as shown in the drawing, and protrudes downward from the lower end surface of the mounting base 22 by a predetermined length. When attached to and attached to the outer cylinder 25A, the outer peripheral surface of the outer cylinder 25A is automatically connected to one terminal 26A for voltage application of the contact sensing means 26 via a brush 27 provided on the attachment base 22. ing. In the illustrated example, the brush 27 has a configuration in which a rotary roller-type electronic device is held by a spring, but is not limited thereto. The other terminal 26B for voltage application of the contact sensing means 26 is connected to a reference sphere 9 which is one reference member for contact sensing in the case of illustration, but instead of the reference sphere, a workpiece not shown in the figure. 8 and a predetermined reference portion such as a processing table.
[0031]
Contact sensing using the electrode guide 25 of the present invention with the above configuration is performed as follows. Particularly important is that contact sensing is performed using the outer peripheral surface 25E protruding a predetermined length from the lower surface of the guide mounting base 22 of the electrode guide 21, and the electrode 18 is not used, and more specifically, the electrode guide 25 is set. After that, before the electrode 18 is inserted and set in the electrode guide 25, the contact is sensed. The predetermined length of projection of the electrode guide 25 is selected to be about 3.5 mm or more when the diameter of the reference sphere 9 is φ5 mm, for example.
[0032]
Hereinafter, the case where the reference sphere 9 is used will be described. The case where contact is detected with respect to the workpiece 8 without using the reference sphere 9 is the same, and the description is omitted. First, as in the prior art, the reference sphere 9 and the workpiece 8 are arranged so that their relative positions are constant. And the relative positional relationship is memorize | stored in the control apparatus beforehand as coordinate value reference data, such as a predetermined part.
[0033]
Next, an electrode guide 25 having a guide hole 25C and a die guide 25D corresponding to the diameter of the narrow hole processing electrode 18 is mounted on the guide mounting base 22, and an outer peripheral surface 25E protruding below the mounting base 22 of the electrode guide 25. Detects contact with the reference sphere 9. The contact sensing operation by the electrode guide 25 is the same as that in FIG. 7, and the operation diagram is omitted, but FIG. 3 illustrates the mode of the operation.
[0034]
The touch sensing is performed by a touch sensing program created in advance by an operator. In this program, since the position of the reference sphere 9 is set in advance to one origin as described above, the electrode guide 25 moves relative to this origin to perform contact sensing. First, the electrode guide 25 moves to a predetermined position above the origin of the reference sphere 9, and then moves to a position separated by a predetermined distance, for example, in the X axis + direction. Next, the electrode guide 25 is sufficiently lowered in a range in which the lower surface of the guide mounting base 22 is located above the top of the reference sphere 9, and then horizontally toward the reference sphere 9, that is, for example, the X axis − Move in the direction. When a detection signal 26C is output from the contact sensing means 26 to a control device (not shown) at a position where the reference sphere 9 and the cylindrical outer peripheral surface 25E of the electrode guide 25 are sensed in a predetermined contact, the coordinate position of the electrode guide 25 is transferred to the control device. The electrode guide 21 returns to the position where the horizontal movement is started.
[0035]
Next, the electrode guide 25 ascends from there, and this time moves to a position that is symmetrical to the previous position with the reference sphere 9 in the horizontal direction, for example, a position that is a predetermined distance away in the X-axis direction. Similarly to the previous step, the electrode guide 25 descends to a height that does not interfere with the guide mounting base 22, and moves horizontally toward the reference sphere 9, that is, for example, in the X axis + direction. Then, the coordinate position where the contact is sensed is stored in the control device, and the electrode guide 25 returns to the start position of the horizontal movement. From there, the electrode guide 25 rises and returns to above the reference sphere 9.
[0036]
The control device calculates the center coordinate position of the two coordinate positions of the stored electrode guide 25, and uses the coordinate position as the center position of the electrode 18 in the current movement axis direction. Stored as the X-axis coordinate position.
[0037]
For the other orthogonal axis of the horizontal plane, the reference sphere 9 and the electrode guide 25 operate in the same manner, and the control device calculates the center coordinate position, in the above example, the Y-axis coordinate position of the center of the electrode 18. Remember.
[0038]
Thus, the center coordinate position of the electrode guide 25 is automatically set so as to exactly match the center position of the reference sphere 9, and as a result, the center position of the electrode guide 25 is stored in the control device as the center position of the electrode 18. The This is because the outer peripheral surface 25E of the electrode guide 25, the guide hole 25C, and the die guide 25D are formed accurately and concentrically. Based on the positional relationship of the workpiece 8 with respect to the reference sphere 9, the electrode 18 is accurately positioned at a desired processing position of the workpiece 8.
[0039]
By the way, the lower end surface of the electrode guide 25 must maintain a predetermined gap close to the workpiece upper surface during electric discharge machining. However, when the electrode guide 25 is replaced in accordance with the electrode diameter, the height position of the lower end surface of the electrode guide 25 with respect to the lower end surface of the mounting base 22 is shifted. Therefore, conventionally, an operator inserts a gap gauge between the electrode guide and the workpiece, and these gaps are confirmed and adjusted. However, since the fine hole electric discharge machine of the present invention can sense the electrode guide lower end surface 25F with respect to the reference sphere 9, the height position of the electrode guide lower end surface 25F is detected by contact sensing. Based on the vertical position, the electrode guide 25 can be adjusted by driving the W-axis slider body 12A with respect to the workpiece upper surface height position. This eliminates the need for checking the gap between the electrode guide lower end surface 25F and the upper surface of the workpiece 8, and also automates the gap adjustment. Note that the height positions of the reference sphere 9 and the workpiece 8 are obtained accurately and easily by previously sensing the reference sphere 9 and the workpiece 8 in the vertical direction with the stylus 40 in advance. Yes.
[0040]
In the positioning of the lower end surface, the lower end surface 25F of the electrode guide 25 senses contact with the reference sphere 9 in the vertical direction, and the detected lower end position is stored as the lower end surface position of the electrode guide 21. Set as a value. That is, first, the electrode guide 25 moves to a position above the reference sphere 9 where the center of the electrode guide 25 is separated from the center of the reference sphere 9 by a predetermined distance in the horizontal direction. At that position, the electrode guide 25 descends until the reference lower end surface 25F comes into contact with the reference sphere 9, and senses contact. Then, the W-axis coordinate position sensed by contact is stored, and the electrode guide 25 is raised to the lowering start position.
Thus, the height position of the lower end surface 25F of the electrode guide 25 is converted into the height position of the lower end surface 25F of the electrode guide 25 by the control device and stored. Based on the height positional relationship of the workpiece 8 with respect to the reference sphere 9, the electrode guide 25 is automatically positioned at a predetermined interval close to the upper surface of the workpiece 8 before the electric discharge machining is started.
[0041]
FIG. 4 shows that the tip of the electrode guide protruding downward from the lower end surface of the mounting base 22 is protected and good when the process proceeds to the implementation of the small hole electric discharge machining after the height position of the lower end surface 25F of the electrode guide 25 is detected. 1 shows an example of a protective cap 33 and its attaching / detaching mechanism for ensuring a safe processing environment. The protective cap 33 is a plate-like body that is slightly thicker than the downward projecting length from the lower end surface of the mounting base 22 of the electrode guide 25, and has a through hole 33A into which the tip of the electrode guide 25 is inserted. The attaching / detaching mechanism includes a cylinder 33B for inserting / removing the protective cap 33 to / from the tip of the electrode guide 25 via an appropriate manipulator mechanism, and a cylinder 33C for reciprocating between the inserting / removing position and the retracted position in the illustrated embodiment. In this case, the connection bracket 23 is provided. In this way, a small space is formed around the electrode 18 on the surface of the workpiece 8 while the protective cap 33 is in contact with the area around the electric discharge machining portion on the upper surface of the workpiece 8 and the lower end surface of the mounting base 22. Since the processing is allowed to proceed in this state, the processing is performed without any trouble in discharging the processing liquid and processing waste, and wear of the lower end surface 25F of the electrode guide 25 can be avoided.
[0042]
FIG. 5 is a side view of an essential part of another embodiment of the present invention, similar to FIG. 3, and shows a plurality of electrode guides 25 corresponding to the narrow hole processing electrodes 18 having the same or different diameters. A mounting base 22B that can be rotated and indexed equivalent to the guide mounting base 22 closest to the electric discharge machining portion is held at a predetermined interval on a straight line or arc line in a direction crossing the axial direction of the electrode, and a plurality of electrodes can be used as required. One of the guides 25 can be positioned on the electric discharge machining portion by the movement in the crossing direction.
[0043]
In the case of the illustrated embodiment, the mounting base 22B is a disc-like body, and is formed on a same arcuate line of equiangular divergence, preferably a plurality of electrode guide holding portions 22B-1, which are preferably electrically insulated from each other. , 22B-n, the center of which is connected to a rotary shaft 28A of a servo motor 28 to which a rotary index detection control rotary encoder 28B is attached, and the servo motor 28 is connected to a W-axis slider main body 12A by a connecting bracket 23. By being supported, the mounting base 22 </ b> B is controlled to move up and down integrally with the W-axis slider 12. Each of the electrode guides 25-1,..., 25-i,..., 25-n has the holding portions 22B-1,. As shown in the enlarged sectional view of the portion of FIG. 6, for example, as shown in the enlarged cross-sectional view of FIG. 6, an appropriate connector such as a ribbon shape in which the top arc surface of the outer cylinder 25A that is the conductive material of the electrode guide 25-1 29A-1 is provided, and is held by the mounting base holding portion 22B-1 in a state of being in contact with the connector 29A-1.
[0044]
When it is attempted to start the fine hole electric discharge machining, or when the inner sleeve 25B or the die guide 25D of the electrode guide 25 being used is repeatedly executed and is worn or damaged beyond a predetermined limit, or the next machining is performed. When the hole diameter of the power hole is different from that of the hole diameter processed so far, the control device (not shown) drives the servo motor 28 according to the detected signal and the decoded NC program. And control the mounting base 22B while receiving the detection feedback signal of the rotary encoder 28B so that the holding portion 22B-1 of the mounting base 22B holding the target electrode guide 25-1 is positioned on a predetermined electric discharge machining portion. Rotate to position and stop. At this time, the terminal 29B-1 at the other end of the connector 29A-1 that is in contact with the electrode guide 25-1 is one of the voltage applied by the contact sensing means 26 on the terminal block 30 provided on the shaft 28A. The terminal 26 </ b> A is insulatively guided from the connector 29 </ b> A- 1 so as to come into contact with the brush 31 to be connected.
[0045]
And according to this invention, each electrode guide 25-1, ..., 25-n which has the structure of the above-mentioned this invention is set to each holding | maintenance part 22B-1, ..., 22B-n of the attachment base 22B. Since it is attached in a state of projecting a predetermined length downward from the lower end surface, contact detection in the horizontal biaxial direction between the predetermined reference sphere 9 and the cylindrical outer peripheral surface 25E of the electrode guide 25-1 is performed. In addition to detecting the position of the center and the end face by the vertical direction, the vertical direction by the W axis between the concentric circular reference lower end face 25F centering on the guide hole 25C of the electrode guide 25-1 and the reference sphere 9 , The position of the lower end surface 25F of the electrode guide 25-1 can be detected.
[0046]
Although the present invention has been described with reference to the illustrated embodiment, it is apparent that the present invention can be implemented by changing each part without departing from the spirit of the present invention. For example, in place of the disk-like body of the mounting base 22B in which a plurality of electrode guides exemplified in FIG. 5 are installed in advance or the rotation indexing mechanism thereof, the present invention is placed at a predetermined interval in the linear direction on the mounting base of the linear body. A plurality of electrode guides depending on the structure, and the linear mounting base uses a servomotor-controlled ball screw or rack and pinion with position detection feedback function, or a linear movement mechanism such as a piston-actuated cylinder actuator mechanism It seems that you can.
[0047]
【The invention's effect】
As described above, according to the fine hole electric discharge machine of the present invention, since the electrode guide having a specific shape, precision configuration and assembly configuration is contacted with the reference sphere instead of the electrode, the electrode guide center position is obtained. The electrode center position can be accurately determined without being affected by the rigidity of the electrode. In addition, since the electrode does not collide with the reference sphere or the workpiece by contact sensing, the tip of the small hole machining electrode is not damaged before the electric discharge machining is started. In addition, since the electrode guide lower end surface can be positioned by the narrow hole electric discharge machine of the present invention, it is not only necessary to check the gap between the electrode guide lower end surface and the workpiece upper surface, but also the gap adjustment is automated. .
[0048]
Further, when the electrode guide is detachably exchanged with the guide device, or when the electrode guide is moved and exchanged in the guide device, a contact sensing voltage is selectively applied only to the exchanged electrode guide. Since it is configured, the center position of the electrode and the end face position of the electrode guide can be more simply, accurately and automatically.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an embodiment of an electrode guide portion of an electrode guide device of the present invention.
FIG. 2 is a longitudinal sectional view of another embodiment of an electrode guide portion.
FIG. 3 is an enlarged cross-sectional view of a main part of an embodiment of the electrode guide device of the present invention.
FIG. 4 is a side view of an electrode guide portion at the time of fine hole electric discharge machining.
FIG. 5 is a side view of a main part of a different embodiment.
6 is an enlarged cross-sectional view of a part of FIG.
FIG. 7 is an explanatory view of electrode center positioning by contact sensing.
FIG. 8 is an explanatory diagram of a conventional measurement technique based on touch sensing.
FIG. 9 is a side view in which a part of a main part of a conventional fine hole electric discharge machine is cut away.
10 is a front view showing the thin hole electric discharge machine of FIG. 9 with a cover and the like removed. FIG.
[Explanation of symbols]
1 Small hole electric discharge machine
2 beds
3 Y-axis drive device
4 saddles
5 X-axis drive device
6 tables
7 Processing tank
8 Workpiece
9 Reference sphere
10 columns
11 Y-axis drive device
11A Ball screw
11B electric motor
11C Straight line guidance
11D rotary encoder
12 W-axis slider
12A Slider body
13 Linear motor
13A Magnet plate
13B electromagnet
14 Z-axis slider
15 Spindle rotation drive
16 Machining spindle
18 Fine hole machining electrode
18A electrode holder
19 Guide protection lid
20 Electrode guide device
21, 25, 25-1, 25-n electrode guide
22, 22B, 22B-1, 22B-n Electrode guide mounting base
22A insertion hole
23 Connecting bracket
24 Intermediate guide
25A conductor outer cylinder
25B Inner cylinder ceramic sleeve
25C guide hole
25D Dice Guide
25E cylinder outer peripheral surface
25F Arc bottom edge
25G annular groove
26 Touch sensing means
26A, 26B Touch sensing voltage terminal
27 Brush
28 Servo motor
28A Rotating shaft
28B rotary encoder
29A-1, 29A-n connector
29B-1, 29B-n terminal
30 terminal block
31 brushes
33 Protective cap

Claims (3)

A plurality of electrode guides that pass through the tips of rotating thin hole machining electrodes of the same or different diameters and guide them to the electric discharge machining unit, an electrode magazine that stores the desired number of electrode guides, and an electrode guide attachment of the electric discharge machining unit In the electrode guide device of a fine hole electric discharge machine having attachment means for attaching and exchanging with the base,
Each of the electrode guides is a cylindrical body as a whole, has a guide hole through which the electrode is inserted and a positioning guide provided in the guide hole, and is concentric with the positioning guide in the guide hole. A cylindrical outer peripheral surface formed of a conductor material which is formed and is in contact with and away from a reference member for horizontal positioning contact sensing, and the electrode guide is attached to the mounting base of the electric discharge machining portion by the mounting means. The lower end side of the guide is mounted in a state protruding a predetermined length from the lower end surface of the mounting base, and the outer peripheral surface of the guide is automatically connected to one terminal of the contact sensing means at the mounting base portion. An electrode guide device for a fine hole electric discharge machine. A plurality of electrode guides that penetrate the rotating fine hole machining electrodes having the same or different diameters and guide them to the electric discharge machining part, and the plurality of electrode guides on a straight line or arc line in a direction intersecting with the axial direction of the electrodes. An electrode guide mounting base that is held at an interval of, and a driving means that drives the mounting base in the direction intersecting with the axial direction of the electrode and positions one of the plurality of electrode guides on the electric discharge machining portion. In an electrode guide device of a fine hole electric discharge machine having
Each of the electrode guides is a cylindrical body as a whole, has a guide hole through which the electrode is inserted and a positioning guide provided in the guide hole, and is concentric with the positioning guide in the guide hole. A cylindrical outer peripheral surface formed of a conductor material that is formed and made to contact with and separate from the reference member for contact detection in the crossing direction, and the electrode guide is provided at a lower end surface of the guide mounting base of the holding means. The outer peripheral surface of the corresponding electrode guide mounted on the predetermined electric discharge machining portion by the driving means is electrically connected automatically to one terminal of the contact sensing means. An electrode guide device for a fine hole electric discharge machine characterized by comprising a means. The electrode guide further comprises a concentric circular reference lower end surface centered on the guide hole that is in contact with and away from a reference member for positioning contact sensing in the electrode axis direction on the lower end lower surface. An electrode guide device for a fine hole electric discharge machine according to claim 1 or 2.

Images